Thermal properties of sand-based rootzone media modified with inorganic soil amendments

Thermal properties of rootzone media are very important physical factors that affect the energy balance and temperature distribution in the rootzone. Little research has been conducted to evaluate the thermal properties of inorganic soil amendments and their effects on turf quality. The objective of this study was to determine the effect of peat, calcined clay (Profile), calcined diatomaceous earth (Axis), zeolite clinoptilolite, and polymer coated clay (Bio-flex-a-clay) on the thermal characteristics of a sand-based medium. The thermal properties of these amendments alone and mixed with sand were measured using a thermal-time domain reflectromery (TDR) method at various water contents. The temperature effects of these amendments were evaluated in a field study where sand/inorganic amendment mixtures were used as rootzone media of a golf green. Volumetric heat capacities of the pure amendments were significantly different at oven-dried,-400 mm tension, and saturated conditions. When mixed at 85% sand and 15% amendments (v/v), the peat mixture had the highest heat capacity of 2.05×106MJM-3C-1, all other inorganic soil amendments/sand mixtures had higher heat capacity values than that of sand, which was 1.59×106 MJM-3C-1 at -400 mm tension. Sand alone had the highest thermal diffusivity (9.20×10-7 M2S-1) and Axis had the lowest (7.43×10-7 M2S-1) at -400 mm tension. Although these thermal characteristics did not translate into differences in turf quality during most of the season, periodical temperature differences were detected in the rootzones. On August 12, 2001, maximum soil temperature at the rootzone surface reached 45.8°C in the plot treated with Axis when the air temperature was 30.5°C. Direct heat injury on the grasses as a result of those heat pulses was observe

Pan-cancer analysis of whole genomes

Cancer is driven by genetic change, and the advent of massively parallel sequencing has enabled systematic documentation of this variation at the whole-genome scale. Here we report the integrative analysis of 2,658 whole-cancer genomes and their matching normal tissues across 38 tumour types from the Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium of the International Cancer Genome Consortium (ICGC) and The Cancer Genome Atlas (TCGA). We describe the generation of the PCAWG resource, facilitated by international data sharing using compute clouds. On average, cancer genomes contained 4-5 driver mutations when combining coding and non-coding genomic elements; however, in around 5% of cases no drivers were identified, suggesting that cancer driver discovery is not yet complete. Chromothripsis, in which many clustered structural variants arise in a single catastrophic event, is frequently an early event in tumour evolution; in acral melanoma, for example, these events precede most somatic point mutations and affect several cancer-associated genes simultaneously. Cancers with abnormal telomere maintenance often originate from tissues with low replicative activity and show several mechanisms of preventing telomere attrition to critical levels. Common and rare germline variants affect patterns of somatic mutation, including point mutations, structural variants and somatic retrotransposition. A collection of papers from the PCAWG Consortium describes non-coding mutations that drive cancer beyond those in the TERT promoter; identifies new signatures of mutational processes that cause base substitutions, small insertions and deletions and structural variation; analyses timings and patterns of tumour evolution; describes the diverse transcriptional consequences of somatic mutation on splicing, expression levels, fusion genes and promoter activity; and evaluates a range of more-specialized features of cancer genomes